1. Field of the Invention
The present invention relates to an electrolyte-positive electrode structure and a lithium ion secondary battery comprising the same.
2. Description of the Related Art
In recent years, the use of a solid electrolyte instead of a liquid electrolyte (electrolyte solution) as a medium for conducting lithium ions has been studied in lithium ion secondary batteries. The solid electrolyte does not cause leakage of an electrolyte solution and can suppress the growth of a lithium dendrite to prevent the short circuit in the battery.
As the solid electrolyte, for example, there is proposed a solid electrolyte in which a sheet-shaped polymer material is impregnated with a nonaqueous electrolyte solution, the sheet-shaped polymer material containing a glass ceramic powder which is represented, by the chemical formula Li1+x+yAlxTi2−xSiyP3−yO12 (0≦x≦0.4, 0<y≦0.6) and has lithium ion conductivity (see Japanese Patent Laid-Open No. 2001-015164).
The solid electrolyte is sandwiched between a positive electrode and a negative electrode which are respectively separately produced to form a lithium ion secondary battery.
Incidentally, in the lithium ion secondary battery using the solid electrolyte, it is conceived to form the solid electrolyte into a thin film to thereby reduce resistance to increase capacity and output.
However, there is an inconvenience that if the solid electrolyte is formed into a thin film having a thickness of, for example, less than 50 μm, the solid electrolyte itself cannot have sufficient strength and will be liable to be damaged, so the solid electrolyte cannot be formed into a thin film.
An object of the present invention is to provide an electrolyte-positive electrode structure which comprises a thin solid electrolyte and can develop excellent capacity and output, and to provide a lithium ion secondary battery comprising the electrolyte-positive electrode structure, by solving such an inconvenience.